1. Field
The present disclosure relates to a cathode active material, a cathode including the cathode active material, a lithium battery employing the cathode, and a method of preparing the cathode active material.
2. Description of the Related Art
In order to manufacture portable, high performance appliances, compact and light weight lithium batteries for the appliances are employed. Also, in order to be used in electric vehicles and the like, the stability, high-rate characteristics, and cycle-life characteristics of lithium batteries, at a high temperature and a high voltage, are important. To implement lithium batteries satisfying the uses, various cathode active materials have been suggested.
For example, LiCoO2 is a commercialized cathode active material. LiCoO2 is expensive, and has an actual electric capacity of about 140 to about 150 mAh/g, which is about 50% of its theoretical electric capacity.
A lithium metal oxide in the form of Li[LixMe1-x]O2 (x>0, Me is a plurality of transition metals), an over-lithiated transition metal oxide, provides an increased electric capacity of about 250 to about 280 mAh/g. The over-lithiated transition metal oxide has low electric conductivity and thus, has decreased high-rate characteristics and poor cycle-life characteristics.
Thus, a cathode active material that is stable at a high temperature and a high voltage, and has improved high-rate characteristics and cycle-life characteristics is needed.